On Wed, Apr 15, 2009 at 2:33 PM, Paul Smith <phh...@gmail.com> wrote: > On Wed, Apr 15, 2009 at 1:27 PM, Manuel Gutierrez > <manuelgutierrezlo...@gmail.com> wrote: >> I want to fit the model y=a*x^b using nls; where "a" should be different for >> each level of a factor. >> What is the easiest way to fit it? Can i do it with nls? >> I've looked the help pages and the MASS example in page 249 but the formula >> is different and I don't know how to specify it for my model. > > What about linearizing the model with log() and use lm() afterwards?
Oops, sorry, I misread your post -- 'a' changes with the level of a factor. Paul ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.